Bill Hardin’s Lathe Set-Up

August 21, 2003

A lot of people have asked to see my 109.20630 with the VFD to change speed and direction on a three phase, 220 volt, 1/3 HP motor.  This set-up allows speed in the single digits up to the full 1725 rated speed of the motor.  In like time, it can be switched from forward to reverse without stopping the motor.  There are things that are made easier by this, like knurling.

This picture shows the basic setup.  I really had very little choice in laying out the workspace.  In 1948,  Dad and I cleaned out the wash house  (in the early days, coal miners bathed in an outside shed separated from the house.  They did not enter the home until clean.)  Dad put an old wooden kitchen table there and the lathe and vise were mounted exactly as in this picture.  The vise was my grandfather’s and is now over 100 years old.  I first learned to “use” it exactly as it is now.  On the other side of the table, I have a small drill press and a tool grinder.  The lathe is mounted on a drip tray that was made for the current 7 x 12 Chinese lathes sold by almost everyone.  This one  came from Grizzly.

The second photo shows the back side of the bench, and a better view of the drill press and tool grinder.  It only looks like a Baldor, it is really Harbor Freight’s $150 copy.   The other $800 is better spent than for a beginner like me.

You might notice that there is a 2” by 18” steel attached to the bench behind the lathe.  This gives me a convenient place to place my magnetic dial indicator and magnetic small lamp to aid in failing vision.  I can also rotate the light on the tool grinder to even further light my  work.

Both pictures show the VFD mounted on the wall under my beautiful framed drawing and parts list for the 109.20630 that I am using.  To accomplish my task, I had some wiring.  When using a standard 110 volt motor before, I had mounted an inexpensive magnetic switch on the right hand face of the table, just under where my right hand would rest.  Since I now had a completely different set-up, it was necessary to rewire the switch so that it would continue to act in the manner I had grown used to.  The VFD required that one of the internal wires be connected to the terminal bar in order for the motor to run.  The cheap little switch from Grizzly needed to switch 110 volts to activate the switch magnet.  So, I ran a separate 110 volt circuit just to the switch just to activate the contact closure to run the motor.  In the picture of the VFD, you can (barely) see a switch just under the meter.   It  is labeled RUN or STOP.  I disconnected it from the terminal block and substituted my old Grizzly to perform this function.

In order to reverse direction, one of the wires on the terminal strip in the box had to be moved to  a different screw.  Back to Radio Shack for a couple of DPDT toggle switches.  In the picture, the switch is labeled DIRECTION, the  top position is labeled FORWARD and the bottom position is labeled REVERSE.  So, the spindle direction of turn can be changed at any time, even when the motor is running.  The switch on the right is identical, but is labeled POWER, up being ON, down being OFF.  This just turns off the 220 volt single phase power to the VFD.  The meter is labeled FREQUENCY, and determines the speed of the spindle.  There is a direct correlation between frequency and RPM.  I now need to monitor the frequency and make a simple chart to reflect actual RPM.  At the bottom of this, I am going to add the complete specifications of the VFD.  All we really need to know is that the knob on the front of the box takes us from 1 or 2 RPM up to the 1725 RPM specified by the motor.  You need to feed a standard 220 volt single phase wire into the box, and you will get out 220 volt three phase power.

I bought the VFD on eBay for $68, and the new GE 1/3 horsepower motor for $25.  Seems to be the least expensive option to do all this.

I have made several changes to my lathe.  Note the handles on the tailstock, carriage and tool post.  I never could find the wrench when I needed it.   I also am near to using an Atlas milling attachment on my 109.   The picture is a little busy with all that is in the background, but you can see the attachment on top of the cross carriage.  The 109.20630 will not support the Atlas milling attachment.  It has a different compound swivel base.  The swivel base on the 109.21270 is near identical to the Atlas 618 for the base, although it does require enlarging the mounting hole on the swivel base from 1-1/4” to 1-1/2”.  The one in the picture came to me that way, so I see no need to complain.

As you see in the last picture, Earl Bower makes a very sturdy cross carriage slide table.  It comes with a fly cutter and a milling bit holder.  It does not have a Z axis movement in the current version, But I am confident Earl will have one sometime.